Peristaltic pump



July 14, 1964 L. M. cuRRIE PERISTALTIC PUMP Filed June ll, 1962 2 Sheets-Sheet l INVENTOR. AUCH/.1N M. CURRIE BY/ TroRNEY 4July 14, 1964 L. M. CURRIE PERISTALTIC PUMP 2 Sheets-Sheet 2 Filed June 1l, 1962 F'll3-3 LA ucHL/N M. CuRR/f A rv'ozA/e Y United States Patent O 3,140,666 PERISTALTIC PUMP Lauehlin M. Currie, Washington, D C., assignor to American Instrument Company, Inc., Silver Spring,

Fiied .lune 11, 1962, Ser. No. 201,520 Claims. (Cl. 10S-149) This invention relates to pumps of the tube-compressing type, and more particularly to a pump of the type wherein a pumping action is exerted on fiuid in a fiexible tube by compressing a limited portion of the tube and moving the zone of pressure along the tube so that the fluid is caused to move in the direction of said zone of pressure.

A main object of the invention is to provide a novel and improved peristaltic pump of the above described type which is Very simple in construction, which is compact in size, and which is provided with efficient means for smoothly adjusting the amount of pressure exerted on the flexible tube portion thereof.

A further object of the invention is to provide an improved peristaltic pump for moving liquids through a flexible tube at a controlled rate, said pump being inexpensive to manufacture, being durable in construction, being easy to adjust, and requiring a minimum number of parts.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

FIGURE l is a front elevational view of an improved peristaltic pump constructed in accordance with the present invention.

FIGURE 2 is an end elevational View of the pump of FIGURE l.

FIGURE 3 is a transverse vertical cross-sectional view taken substantially on the line 3-3 of FIGURE l.

FIGURE 4 is a horizontal cross-sectional view taken substantially on the line 4-4 of FIGURE 1.

Referring to the drawings, 11 generally designates a peristaltic pump constructed according to the present invention. The pump 11 comprises a generally rectangular motor housing 12 which serves as a support for the pump, said housing having a front wall 13, vertical end walls 14, a bottom wall 15, and a top wall 16.

Secured to the front wall 13 is a boxlike bracket member 17 comprising a rectangular plate-like main wall 18, top and bottom horizontal longitudinal anges 19 and 20, and a vertical end flange 21.

The plate-like main bracket wall 18 is secured to housing wall 13 by a plurality of fastening screws 22, which extend through walls 18 and 13 and threadedly engage in the frame of a horizontally disposed electric motor 23 in housing 12, thus securing the motor to wall 13. The shaft 24 of said motor extends rotatably through walls 13 and 18, and secured on said shaft is a circular spider member 25 provided on its periphery with evenly spaced tube-squeezing cam elements, for example, having evenly spaced anged rollers 26 journalled on its marginal portion. As shown in FIGURE l, the flanged rollers 26 are arranged concentrically around the hub portion 27 of the spider member and are parallel thereto.

As is further shown in FIGURE 1, the spider member 25 is located adjacent the open end of the box-like bracket member 17. A motor control switch 28 is mounted in the housing and has its operating lever 29 exposed in bracket member 17 adjacent the vertical end flange 21.

A relatively rigid, generally L-shaped longitudinally extending guide bracket 30 is secured by a pair of fastening screws 31, 31 on the bottom bracket flange 20 adjacent vertical flange 21. Bracket 30 is provided with the vertically slotted upstanding end arm 31 which is located adjacent the bottom portion of spider member 25, the

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bracket 30 having a main body portion 32 of substantial length which is inclined upwardly and toward said spider bottom portion, as shown in FIGURE l. Clamped between bracket 30 and bottom flange 2G by the fastening screws 31, Which are threadedly engaged in bracket 30, is one end portion of an elongated leaf spring 33, said leaf spring having the upwardly extending arcuate end portion 34 which extends around the lower outer peripheral portion of spider member 25 and which is preferably of sufficient length so that it can span at least two of the rollers 26, whereby it can exert inward compressive force simultaneously on two spaced portions of a flexible tube 35 engaged around the rollers, as shown in FIGURE 1.

A vertical adjustable thumbscrew 36 is threadedly engaged through flange 20, said screw being directed upwardly and engaging the leaf spring 33 adjacent the arcuate portion 34, whereby to regulate the inward force exerted by said arcuate portion on the tube 35, and thereby to regulate the squeezing force exerted on the tube.

The exible tube 35 extends through a rubber supporting stopper 36 mounted in the lower portion of fiange 21, through the guide slot 37 of arm 31, between the rollers 26 and arcuate spring portion 34, around the upper rollers 26, and through the outwardly projecting arm 39 of a right-angled supporting bracket 40. Said bracket 40 is secured by a screw 22 to walls 1S and 13 at a location directly above arm 31. Bracket 46 is formed with a generally keyhole-shaped slot 38, the larger portion of which supportingly receives the flexible tube 35. The outlet portion of said tube passes through and is supported in a keyhole-shaped slot 41 provided in the upper portion of vertical flange 21.

Stopper 36 and keyhole slot 41 exert sufficient frictional retaining force on the tube 35 to prevent its displacement during the operation of the pump.

In operation, motor 23 drives spider member 25 in a counterclockwise direction, as viewed in FIGURE 1, causing the rollers 26 to successively engage and exert squeezing force on the tube, against the yieldable resistance of the arcuate portion 34 of spring 33, the degree of said resistance being adjusted by means of screw 36 in accordance with the nature of the fiuid carried in the tube and in accordance with the desired rate of fiow. The fluid is forced through the tube by the moving zones of compression therein, so that said Huid is steadily pumped through the tube responsive to the continuous counterclockwise rotation of spider member 25.

The relatively rigid bracket 30 serves as a means of reinforcing the secured end portion of leaf spring 33, enabling the screw 36 to be adjusted to provide reliable control of the amount of upward force applied to the arcuate end portion 34 of leaf spring 33, as well as providing a fulcrum or abutment to prevent excessive upward deflection of the portion of the spring adjacent its clamped end. As shown in FIGURE 1, the adjusting screw 36 is preferably located a substantial distance outwardly, namely, to the right, as viewed in FIGURE 1, from the rounded corner 42 defined between arm 31 and the inclined portion 32 of bracket 30.

While a specific embodiment of an improved peristaltic pump has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A peristaltic pump comprising a support, a spider member rotatably mounted on said support, a plurality of tube-squeezing cam elements on said spider member,

said cam elements being spaced around a circle concentric with the axis of said spider member, a leaf spring secured at one end portion to said support and having its other end portion extending outwardly adjacent at least one of the cam elements and being arranged to exert yieldable inward force thereagainst, means to rotate said spider member, and a flexible tube extending between the leaf spring and said one of the cam elements, said leaf spring being resiliently cooperable with the cam elements to produce moving zones of compression along the tube responsive to rotation of said spider member.

2. A peristaltic pump comprising a support, a spider member rotatably mounted on said support, a plurality of tube-squeezing cam elements mounted on said spider member, said cam elements being spaced around a circle concentric with the axis of said spider member, a leaf spring secured at one end portion to said support and having its other end portion extending outwardly adjacent at least one of the cam elements and being arranged to exert yieldable inward force thereagainst, means to rotate said spider member, a flexible tube extending between the leaf spring and said one of the cam elements, said leaf spring being resiliently cooperable with the cam elements to produce moving7 zones of compression along the tube responsive to rotation of said spider member, and an abutment element on the support engaging the intermediate portion of the leaf spring on the side thereof opposite said one of the cam elements.

3. A peristaltic pump comprising a support, a spider member rotatably mounted on said support, a plurality of tube-squeezing cam elements on said spider member, said cam elements being spaced around a circle concentric with the axis of said spider member, a leaf spring having one end secured to said support and extending outwardly adjacent at least one of the cam elements and being arranged to exert yieldable inward force thereagainst, means to rotate said spider member, a flexible tube extending between the leaf spring and said one of the cam elements, said leaf spring being resiliently cooperable with the cam elements to produce moving zones of compression along the tube responsive to rotation of said spider member, an adjustable first abutment element on the support engaging the intermediate portion of the leaf spring on the side thereof opposite said one of the cam elements, and a fixed second abutment element on the support adjacent the secured end of the leaf spring on the side thereof opposite said first abutment element, providing a fulcrum to prevent excessive defiection away from said first abutment element of the portion of the spring adjacent its secured end.

4. The structure of claim 3, and wherein said first abutment element comprises a screw threadedly engaged with the support.

5. The structure of claim 4, and wherein said second abutment element comprises a rigid bar member extending along a substantial length of the spring and terminating short of the location of said screw.

6. The structure of claim 3, and wherein said leaf spring has an arcuate free end portion extending adjacent the cam elements and of sufficient length to span at least two of said cam elements.

7. The structure of claim 3, and wherein said support is provided with an outwardly projecting fiange extending parallel to the axis of said spider member, said abutment members and leaf spring being mounted on said ange.

8. A peristaltic pump comprising a support including a wall, a motor mounted on said support and having a shaft extending through said wall, a circular spider member secured on said shaft, a plurality of rollers journalled on the peripheral portion of said spider member and being spaced around said peripheral portion, a leaf spring secured at one end portion to said support and having a resilient yieldable arcuate opposite end portion located adjacent the periphery of said spider member, said arcuate end portion extending along a substantial portion of said periphery and being arranged to exert inward spring force on the rollers, and a flexible tube extending between said arcuate end portion of the leaf spring and the rollers, whereby said rollers cooperate with said arcuate end portion to produce moving zones of compression in the tube responsive to rotation of said spider member.

9. A peristaltic pump comprising a support including a wall, a motor mounted on said support and having a shaft extending through said wall, a circular spider member secured on said shaft, a plurality of rollers journalled on the peripheral portion of said spider member and being spaced around said peripheral portion, a leaf spring secured to said support and having a yieldable arcuate end portion located adjacent the periphery of said spider member, said arcuate end portion extending along a substantial portion of said periphery and being located to exert inward spring force on the rollers, a liexible tube extending between said arcuate end portion of the leaf spring and the rollers, whereby said rollers cooperate with said arcuate end portion to produce moving zones of compression in the tube responsive to rotation of said spider member, and a rigid abutment member mounted on the support adjacent a portion of the leaf spring spaced from said arcuate end portion and on the side thereof opposite said spider member and being engageable by the spring to limit fiexure of said spring away from said rollers.

10. A peristaltic pump comprising a support including a wall, a motor mounted on said support and having a shaft extending through said wall, a circular spider member secured on said shaft, a plurality of rollers journalled on the peripheral portion of said spider member and being spaced around said peripheral portion, a leaf spring secured to said support and having a yieldable arcuate end portion located adjacent the periphery of said spider member, said arcuate end portion extending along a substantial portion of said periphery and being arranged to exert inward spring force on the rollers, a flexible tube extending between said arcuate end portion of the leaf spring and the rollers, whereby said rollers cooperate with said arcuate end portion to produce moving zones of compression in the tube responsive to rotation of said spider member, and an adjustable abutment screw threadedly engaged with the support and being engageable with said spring to urge said arcuate end portion toward the rollers.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A PERISTALTIC PUMP COMPRISING A SUPPORT, A SPIDER MEMBER ROTATABLY MOUNTED ON SAID SUPPORT, A PLURALITY OF TUBE-SQUEEZING CAM ELEMENTS ON SAID SPIDER MEMBER, SAID CAM ELEMENTS BEING SPACED AROUND A CIRCLE CONCENTRIC WITH THE AXIS OF SAID SPIDER MEMBER, A LEAF SPRING SECURED AT ONE END PORTION TO SAID SUPPORT AND HAVING ITS OTHER END PORTION EXTENDING OUTWARDLY ADJACENT AT LEAST ONE OF THE CAM ELEMENTS AND BEING ARRANGED TO EXERT YIELDABLE INWARD FORCE THEREAGAINST, MEANS TO ROTATE SAID SPIDER MEMBER, AND A FLEXIBLE TUBE EXTENDING BETWEEN THE LEAF 